Brush-gear for dynamo-electric machines.



H, RHMAN @i F. H. PETERS.

BRUSH GEAR FOR-DYNAMO ELECTRIC MACHINES. APPLICATION F!LE'D-FEB.16, 19u.

1,259,672., Patented Mar. 19, 1918,

3 SHEETS-SHEET 3.

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. `l I I VVitesS: I l Inventors.-

saines nfrnnfr Friend mannen, 'or nailart,

'NTLYVY SUIEEL'Y COMPANY, 0F NEWT YORK, N. Y., A CORPORATION entrera-enen. rois nriiario-ntncrnic maestrias.

Specieatior. of Letters Patent.-

iiiia'a 19,1918.-

.application tiled February 16, 191?. 'Serial No. 1485938.

To all 'whom t may concern;

Be it known that we, HAnnr D, Romarin,

a citizen of the Republic or Swi'azerland,A

and FRANK PETERS, a citizen of Great Britain, both residing at New York city, in "the county of 'New4 'York and State et New York, United States of America, have in vented certain new and useful :improve-- dynamos used for train lighting purposes.v

` One of the primary objects of our invention is the provision of an improved brush gearor rigging which is an edective substitute for the special pole changing mechanism customarily employed in train lighting systems to maintain external circuit. Another one of the more important objects of our invention resides in the provision of an improved brush gear wherein the diiiiculties usually encountered with the use of flexible leads for connecting the brushes with the main leads are obviated. i A.

One of the more specific objects of our invention resides in the provision. of an improved, simple, economical and effective brush gear for brushes which swing through the full 'polar arcwhereby flexingof the leads connecting the brushes with the main lead terminals, or external circuitterminals, is entirely eliminated, whereby we are enabled to greatly reduce the cost of main tcnance inclusive of inspection.

' The foregoing, together with such* other objects as may hereinafter appear, or are inciden-t to our invention, we obtain by means of a construction which we have illustrated in preferred iorm in the accompanying drawings, wherein- Figure 1 is an end elevation of a dynamo suitable .for train lighting purposes, in which y the end cap or dust covering is removed so as to expose the brush rigging; Fig. 2 is a section taken on the line 2-2 of Fig.' l, but with thedust cover in position;. Fig. 3 `is a` section through half o the brush rigging constant polarity in theA taken on the line 3-3 lof Fig. 1' lwhile 4 is a diagram showing the inaiiner'in which the device operates eliminating the flexing of the leads as hereinberpore noted.

Vlhile oi3 course it is 'to be understood that our invention is applicable to dynamo electrie machines of various types, we have illustrated our invention as' applied to a dynamo for generating" current to supply the bat'- lteiies and the customary circuits of a train lighting system such as usedo'n railway and other vehicles. Our invention is particularly valuable for two-pole machines, itorit maires it possible to use the rotating; type of brushes with suoli machines. We have there- .tore speciiically shown our invention as applied to this type 'of dynamo in. which the brushes swing through. the full polar are of 180o. lt will be 'at once apparent to those skilled 'in the art that the improvcmentsinay be applied to a four-pole machine, forcenample, or other inulti-polar machine.

`vReferring now particularly to Figs, 1 and EZ the numeral '7 denotes the ma -net' frame 7 u c u of the dynamo in which the armature spindle or shaft 8, the commutator 9, and the .ar` mature 1() are rotatably mounted in suitable' bearings. A front head or .ring 111s secured to the outer face of thecasing 7 which accommodates the forward end of the armature shaft, with its bearing A. This bearing A is of the ball bearing orf any other preferred type. rl`he tivo carbon brushes B and C (generally indicated in Fig. 1 and specifically in Fig. 3) are mounted in the brush holders 12 which in turn are -*secured to the rocker 13 which in turn is mounted on ball bearings 15 on the ring portion 11 ot the front head'. The brush holders are secured to the rocker 13 by means of the studs 1(3'and 17, the brush holders being insulated 'from the rocker 13 by means of insulation plates 18, and insulate-,d from the studs 16 and 1'? by insulatingr sleeves 19. Projecting from the rocker 13 is a stop pin 20 adapted to come against either one oi* the two stops 21 at cX-l tremes of rotation through the full polar arc.

r[he stops 21 are formed on the front housing.

this arrangement, the movement of the' brush holders -in either direction is limited at the proper place to secure goed commutation. it will be understood 'of course that the carbon brushes B tand C are yieldingly held iii engagement? withl the commutator 9 insulation 26'. The means whereby current is conducted from the brushes to the main or external circuit terminals 24 and 25 will now be described.

The brush holder 12 for the brushes B carries two brass or copper extension mentbers or arms..27 and 28, such arms being secured in place by the same studs 16 and 17 which serve to fasten the said brush holder 12toI the front head (see Fig. 3). The arm 27 is in electrical contact with the brush holder -12 but is insulated from the studs 16 and 17 by means` of the insulating sleeves 19. The arm 28 is insulated from the arm 27 and also from the said brush holder 12 by means of the insulation 29 and it is insulated from the studs 16 and 17 by the insulating sleeves 30, the plate 31 against which the heads or nuts of the studs abut when all the parts are tightened up, is insulated from the parts thus far described by means of the insulation 32. The arms 27 and 28 have their end portions 27a and 28 bent downwardly and spaced apart and are apertured to receive a small shaft or spindle 33 which is provided with an insulatin sleeve 34, the nut 35 for securing the spin e being also insulated from the port1on 27. vMounted on the insulating sleeve 34 between the portions 27a and- 28 of the arms is a round Contact piece 36 which i's in electrical contact with the extension 2", but is insulated from the extension 28a by means of the insulating disk 37. 'Mounted on the sleeve 34 on the outside of the extension 28, biit in electrical contact therewith is a second round contact piece 38 which is insulated from the head of the shaft 33 by the insulating disk 39.

Mounted on the end yplate 23 is a second shaft orspindle 40, the position of which is y to be hereinafter more specifically pointed out. On the shaft 40 is an insulating sleeve 41 which -carries the following parts: namely, the positive main terminal 24, (insulated from the 'end plate 23 by insulation 26).; the round contact piece 43 which is in electrical contact with the terminal 24, the mainor external negative terminal 25 (insulated from the contact piece 43 by the insulating disk 44); the contact piece 45, in

electrical contact With the terminal 25, but

' insulated from the head or end of the shaft 40 by the insulating disk 46. The terminal i5 25 .s stepped or bridged as at 25a so that it can be securely fastened to the end plate or switch board 23 by the screw 25". The terminal 24 is similarly secured. By the .foregoing arrangement, it will be seen that the parts arel so arranged and mounted that access can be readily had to the bearing parts, and that the various parts -can be readily assembled or taken apart.

Electrical connection is had between the contact piece 36 and the contact piece 43 by means of the flexible strap 47 and electrical connection between the contact piece 38 and the contact piece 45 is had by thc flexible strap 48. These straps (see Fig. 4) are secured vto the contact pieces by suitable fastening means such as the screws 49. The strap or yoke 50 (see Figs. 1 and 3) connects the brushes C with the arm 28. The path of current is as follows: Assuming that the brushes B are positive, the current collected by the brushes B passes through the respective brush holder 12, through arm 27 and extension 27, through contact piece 36, strap 47, Contact piece 43, terminal 24, thence to the external circuit, returning by the negative main return to terminal 25, thence to Contact piece 45, strap 48, contact piece 38, extension 28, arm 28, strap 5() to brushes C. Assuming now that the direction of train travel is reversed, the friction of the brushes on the commutator will cause the brush ring to reverse through the full polar arc until the pin 20-co1nes up against the respective stop 21. The signs of the 100 brushes will therefore remain the same. While the brush rigging is swinging through the full polar arc on reversals, the straps 47 and 48 will be wound on the Contact pieces 43 and 45, the particular arrangement of the 105 stationary contact pieces with respect to the moving parts being as follows:

From inspection of Fig. 4 it will be seen that we have diagrammatically represented the fixed or stationary contact pieces at D; 110 the movable contact pieces at E and the two connecting straps or leads at F; the center of the armature spindle at O; while E represents the position of the movable contact pieces on the brush rigging when the 115 brushes have been reversed 180o, that is to say, when vthe position of the brushes is exactly transposed. The distance a which represents the distance between the center line of the armature spindle and the center of spindle 40 is equal to one quarter of the periphery of the contact pieces 43 and 45; the distance b represents the distance between the center lines of the spindles 40 and 33; and the distance 0 represents the 126 distance between the center line of the armature spindle and the center of spindle 33,

e., the distance c is the sum of the distances a and b; It will be seen therefore that when the contact pieces 36 and 38 are moved from the position indicated in full 'lines' at E 180O to the position indicated in dotted lines at E, the straps 47 and-48, as represented at F, will assume the dotted line position between D and E. Now, since the distance between the center lines at D and E equals c-i-a or b-l-Q, which is the length of the strap, it will be seen that the straps at no time are slack but simply unwind themselves on the stationary contact pieces, and that while the straps are wrapped around the stationary rollers, the flexing is distributed over half` the periphery of the stationary rollers, or over the distance equal to 2a. Therefore in general, it may be said that the flexing ofthe leads or straps is negligible and can be considered as non-existent in comparison to. the flexing which takes place in standard switch gear constructions in which the brushe swing through-the full polar arc.I

lThe advantage of the arrangement willr be apparent to those skilled in the art, for it will be seen that it eliminates the diiculties which are encountered in standard constructions because of the flexing of the leads which connect the brushes with the external terminals which results in frequent breakage and necessitates frequent examination and repair by maintenance force and avoids the careful location of the iiexible leads otherwise necessary. At the same time the construction is simplefinexpensive, shortcircuiting is effectually prevented, and all prts of the apparatus at the commutator end of the machines are readilyaccessible for purposes ofl cleaning, repair or examina-V tion. Aspointed out, the invention is particularly valuable because it makes it possible to utilize rotating brushes on two-pole machines. Acertain measure of the advantage incident to our invention may also be obtained even if the spindle 40 is not eccentrically located.`

We claim: y

I 1. A reversing brush gear for dynamo electric machines comprising a rocking brush holder, a lead or conducting the current having one end supported from said holder,

and an achoring member. about which thev l other en'd of said lead is wrapped.

2. A reversing brush gear for dynamo electric machines comprising a rocking brush holder, a lead for conducting the current having one end supported from said holder, and a stationary anchoring member located eccentrically with respect to the center of signed our names.

rotation of the brush holder and about which the other end of said lead is wrapped.

3. A reversing brush gear for dynamo electric machines comprising a pair of brushes, a rocking brush holder therefor, a pair of leads each of which is in electrical connection with a brush and each of which is supported from the brush holder, and an anchoring member about which said leads are wrapped.

4. A Areversing brush gear for dynamo electric machines comprising a pair of brushes, a rocking brush holder'therefor, a pair of supports at one side of said holder, one in electrical connection with one brush and the other with the other brush, a pair of leads each connected to one of said supports, and a pair of stationary members about which said leads are wrapped electric machines comprising a pair of brushes, a rocking brush holder therefor, a pair of conductors mounted on one side of said brush holder and each having means 5. A reversing brush gear for dynamo Y for supporting a lead, one of said conductors being 1n electrical Connection with one brush and a strap for electrically connecting the other conductor with the other brush, a lead connection to each conductor, a pair of relatively ixed supporting means aboutV which said leads are wrapped and-means whereby said supporting means are connected 'with external circuit terminals.

6. A reversing brush gear for dynamo electric machines comprising a rocking brush holder therefor, a pair of conducting arms mounted on said brush holder, oneo said arms being electrically connected to one brush and the other to the other brush, a pair of drum-like lead supports mounted in said `arms each of which is in electricarcon- 's nection with one arm, a pair of rea hXed drum-like anchoring members, lead connectlng each lead support to a lenig' choring member, said leads being wrapped aboutthe anchoring members.

7. A rocking brush gear for dynamo electric machines comprising a rocking brush holder, a lead for conducting current having one end supported from said holder and extending from the brush holder in a direction inwardtoward the centerof rotation, and means 'for supporting the other end of saidflead.

In .testimony whereof we have hereunto ROHMAN. 

